Age and tectonic setting of Late Archean greenstone-gneiss terrain in Henan Province, China, as revealed by single-grain zircon dating

Journal Article · Tue Mar 01 04:00:00 EST 1988 · Geology; (United States)

DOI:https://doi.org/10.1130/0091-7613(1988)016<0211:AATSOL>2.3.CO;2· OSTI ID:6894998

Kroener, A; Compston, W; Guo-wei, Z; An-lin, G; Todt, W

The authors report precise U-Pb zircon ages for single grains of a metarhyodacite from the Late Archean Dengfeng greenstone belt in Henan Province, China, near the southern margin of the North China craton. Most grains belong to an igneous population whose U-Pb isotopic systematics define a straight line intersecting concordia at 2512 +/- 12 Ma, and this is interpreted as the time of crystallization of the original greenstone volcanics. Several grains are distinctly older, between 2576 +/- 9 and 2945 +/- 44 Ma, and the authors interpret the older grains as xenocrysts of pre-greenstone continental crust that provide evidence for crustal derivation or crustal contamination of the original rhyodacitic lava. The xenocrysts suggest evolution of the Dengfeng greenstone belt in a continental environment that may be represented by the Taihua high-grade gneisses bordering the Dengfeng greenstones and for which the authors obtained ages of 2806 +/- 7 and 2841 +/- 6 Ma. The data add evidence to the now widely held concept that most Archean greenstones developed on or near older continental crust and were therefore prone to crustal contamination. In such cases, conventional zircon dating may not always record the precise age of rock formation.

• Research Organization: Univ. of Mainz (West Germany)
• OSTI ID: 6894998
• Journal Information: Geology; (United States), Journal Name: Geology; (United States) Vol. 16:3; ISSN GLGYB
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580100* -- Geology &amp; Hydrology-- (-1989)
ACTINIDES
AGE ESTIMATION
ASIA
CHINA
CONTINENTAL CRUST
EARTH CRUST
ELEMENTS
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
GNEISSES
ISOTOPE DATING
LEAD
METALS
METAMORPHIC ROCKS
MINERALS
OXYGEN COMPOUNDS
ROCKS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
TECTONICS
TRANSITION ELEMENT COMPOUNDS
URANIUM
ZIRCON
ZIRCONIUM COMPOUNDS
ZIRCONIUM SILICATES